Following the recommendation on another thread, putting up the details of my build here to ask for recommendations on things can be improved.    We're not aiming for a Passivhaus level of spec, as the law of diminishing returns means that the payback probably is not worth it. Aiming for a Building Regs compliant comfortable family home - and this is going to be a massive step up from a 1930s semi with no cavity wall (where we currently live).    Ground floor is Beam and Block